Application Guide

P a g e | 46
DP750/DP720 Administration Guide
Version 1.0.3.37
Preferred Vocoder
Configures vocoders in a preference list (up to 8 preferred vocoders) that will be
included with same order in SDP message. Vocoder types are G.711 A-/U-law,
G.722, G.726-32, G.723, G.729, iLBC and OPUS
Voice Frames per
TX
Transmits a specific number of voice frames per packet. Default is 2; increases to
10/20/32/64 for G711/G726/G723/other codecs respectively.
G723 Rate
Operates at specified encoding rate for G.723 vocoder. Available encoding rates
are 6.3kbps or 5.3kbps. Default is 6.3kbps.
G726-32 Packing
Mode
Defines G726-32 packing mode (“ITU” or “IETF”). Default is ITU.
iLBC Frame Size
Specifies iLBC packet frame size (20ms or 30ms). Default is 20ms.
iLBC Payload type
Determines payload type for iLBC. The valid range is between 96 and 127.
Default is 97.
Disable OPUS
stereo in SDP
Disables OPUS stereo attribute in SDP header. Default is No.
OPUS Payload Type
Determines OPUS payload type. The valid range is between 96 and 127.
Default is 125.
Use First Matching
Vocoder in 200OK
SDP
Includes only the first matching vocoder in its 200OK response, otherwise it will
include all matching vocoders in same order received in INVITE. Default is No.
SRTP Mode
Selects SRTP mode to use (“Disabled”, “Enabled but not forced”, or “Enabled and
forced”). Default is Disabled.
It uses SDP security description to exchange key. Please refer to:
SDES: https://tools.ietf.org/html/rfc4568
SRTP: https://tools.ietf.org/html/rfc3711
Crypto Life Time
Adds crypto life time header to SRTP packets. Default is Yes.
Silence
Suppression (VAD)
Allows detecting the absence of audio and conserves bandwidth by preventing the
transmission of "silent packets" over the network. Default is No.
Jitter Buffer Type
Selects jitter buffer type (Fixed or Adaptive) based on network conditions.
Jitter Buffer Length
• High (initial 200ms, min 40ms, max 600ms) Note: not all vocoders can meet
the high requirement.
• Medium (initial 100ms, min 20ms, max 200ms).
• Low (initial 50ms, min 10ms, max 100ms).
Enable RTCP
Enables RTCP statistics and control information. Default settings is RTCP.